Separation of aromatic compounds by forming clathrates with werner complexes of 2-arylalkylamines

ABSTRACT

The invention comprises a Werner complex of the general formula Ni(SCN)2Xn which is insoluble or sparingly soluble, in water at room temperature, wherein X is an alpha-arylalkylamine of the formula &lt;FORM:0994026/C2/1&gt; in which R1 is either hydrogen or a primary alkyl group and R2 is a phenyl radical carrying at least two further alkyl substituents in any of the 3-, 4- and 5-positions, and n is either 2 or 4. Preferably R1 contains 1 to 6 carbon atoms and the alkyl substituents of the phenyl radical have not more than two carbon atoms.  The complexes may be made, for example, by adding a solution of the arylalkylamine in heptane, or heptane-chloroform mixture, at room temperature to an aqueous solution obtained by dissolving NiCl2.6H2O and KSCN in water, and separating the resulting precipitate by filtration. The complexes may be used to form clathrates with aromatic compounds and the complex may be formed in the presence of the compound to be clathrated.  The clathrate may be formed by heating a complex Ni(SCN)2X4 with one or more clathratable compounds to a temperature sufficient to bring about complete dissociation of the complex into Ni(SCN)2X2 and free amine, and then cooling to effect recombination of the dissociated components to form a clathrate consisting of Ni(SCN)2X4 and the clathratable compound. The complexes of the formula Ni(SCN)2X4 may be used to resolve a mixture of aromatic organic compounds containing at least one clathratable compound by forming a clathrate, separating the clathrate from the mixture and dissociating the clathrate to recover the organic compounds. The clathrate may be dissociated by heating, by treatment with an acid which does not react with the clathrated compound, by steam stripping or treatment with an inert solvent. Clathratable compounds which may be extracted or resolved are, for instance, a ,a ,a -tri -fluorotoluene, nitrobenzene, nitrotoluenes, di-, chlorobenzenes, trichlorobenzenes, cresols, and benzonitrile. Novel amines which are suitable for complex formation are a -(3,4-dimethyl phenyl) ethylamine and corresponding butylamine and heptylamine; a  - (3,4,5 - trimethylphenyl) - ethylamine and - propylamine; a -(3,5 - dimethylphenyl) ethylamine and a -(3,4,5 - triethylphenyl) ethylamine.  They may be made by reductive amination of the corresponding ketone, for example by heating the ketone with ammonium formate.  Specifications 931,775, 935,099 and 945,012 are referred to.

Aprll 6, 1965 3,177,266

P. M. J. G. DE RADZITZKY DOSTROWICK ETAL SEPARATION OF AROMATICCOMPOUNDS BY FORMING CLATHRATES WITH WERNER COMPLEXES 0F2-ARYLALKYLAMINES Filed May 22, 1963 3 Sheets-Sheet 1 MOLALITY OF lPHENYLETHYLAMINE 1o"/T'K DISSOCIATION OF THE COMPLEX [Ni(SCN)(q-PHENYLETHYLAMIND J IN O-XYLENE AND n- HEPTANE O INCREASINGTEMPERATURES IN O-XYLENE A DECREASING TEMPERATURES 0 INCREASINGTEMPERATURES m n-HEPTANE A DECREASING TEMPERATURES THE CONCENTRATION OFAMINE IS EXPRESSED m MOLAL|TY(MOLES 0F AMlNE/KG OF SOLVENT) FIGJINVENTOR5 P/f/QRE MM/E JOSEPH GHI$LAIIV ah RADZ/TZKYd'OSTRDW/ K JACQUESDAN/5L warm HANOT/ER A nl 6, 1965 3,177,266

P. M. J. G. DE RADZITZKY D'OSTROWICK ETAL SEPARATION OF AROMATICCOMPOUNDS BY FORMING CLATHRATES WITH WERNER COMPLEXES OFZ-ARYLALKYLAMINES Filed llay 22, 1963 Sheets-Sheet 2 mm Hg THERMALmssocmnou or- THE COMPLEX [nuscm PHENYLETHYLAMINE AND 11s o-xvuzm:CLATHRATE o VAPOUR PRESSURE OF PHENYLETHYLAMINE A VAPOUR PRESSURE 0FO-XYL-ENE o mssocmnou PRESSURE OF THE COMPLEX [m scu aPHENYLETHYLAMINE)4] A mssocmnou PRESSURE OF THE O-XYLENE CLATHRATE nmssocmnou PRESSURE OF THE COMPLEX [Ni(SCN) u PHENYLETHYLAMINQZ] FIG. 2

INVENTOR. PIERRE MAR/E JOSE/W emu/1v dekADZIHKYd'OSTKOW/CK JACQUESDAN/EL v/crm HANOVER April 6, 1965,

Filed May 22, 1963 mm Hg P. M. J. G. DE RADZITZKY D'OSTROWICK ETALSEPARATION OF AROMATIC COMPOUNDS BY FORMING CLATHRATES WITH WERNERCOMPLEXES OF 2-ARYLALKYLAMINES 3 Sheets-Sheet 3 THERMAL mssocmnou OF THECOMPLEX [nuscm (a-msmvwvmommd AND ITS p-XYLENE CLATHRATE ."VAPOURPRESSURE OF b-METHYLPYRIDINE A IAPOUR PRESSURE OF p- XYLENE o mssocmnouPRESSURE OF THE commsxfimscm (4-usmvp vmomm A DISSOCIATION PRESSURE OFTHE p-XYLENE CLATHRATE VAPOUR- PRESSURE OF p-XYLENE LIBERATED FROM THECLATHRATE F IG. 3

INVENTOR.

P/ERRE MAR/E JOSEPH GHLSLAl/V de moz/rz/o d'OSfROW/CK JACQUES DAN/ELVICTOR HA/YOT/ER Avomap United States Patent 3,177,265 SEPARATION OFAROMATIC COMPOUNDS BY FORMING CLATHRATES WITH WERNER (30M- PLEXES 0FZ-ARYLALKYL .r- X Pierre Marie Joseph Ghislain do Radzitzky dflstrowickand Jacques Daniel Victor Hanotier, Brussels, Belgium, assignors toLabofina, Brussels, Belgium Filed May 22, 1963, Ser. No. 282,429 Claimspriority, application Great Britain, May 31, 1962, 21,098/ 62; June 4,1962, 21,532/62 4 Claims. (Cl. 260-674) This invention relates to aprocess of clathration of organic compounds by means of Wernercomplexes.

This application is a continuation-in-part of application Serial No.143,030 filed October 3, 1961, now abandoned, which is acontinuation-in-part of application Serial No. 855,957, filed November30, 1959, now abandoned.

The formation of interstitial compounds, of which clathration is aparticular case, has been known in a general manner for some years. Inthese compounds, molecules of one constituent are included in the spacesexisting between the molecules of the crystal lattice of the otherconstituent. In clathrates as described by Powell (J. Chem. Soc. London61-73, 1948), the clathrated molecules are lodged in the spaces in thelattice of the host compound and no chemical interaction between the twoconstituents is claimed to exist. Today, however, the term clathrate isnot confined to compounds in which the two constituents are associatedby a purely mechanical relationship. In particular, in the clathratesformed by Werner complexes it is possible to have a number of forms ofassociation between the two constituents of the clathrate, although theinteraction is predominantly mechanical and physico-chemical. Thus thepresent invention is not to be considered as limited to clathrates whichexhibit a purely mechanical inclusion of one constituent in the latticeof the other.

Clathration of aromatic hydrocarbons in accordance with this Widerdefinition has been described in United Kingdom Patent No. 811,137, andin several United States Patents Nos. 2,849,513; 2,849,511; 2,798,891;2,798,103; 2,798,102; and 2,774,802. The process of clathrationdescribed in these patents is capable of bringing about the resolutionof mixtures of compounds. It is especially applicable to the selectiveisolation of paradisubstituted aromatic compounds. Thus a mixture of thethree cymenes can be highly enriched in p-cymene in only one step. Theclathration described in these patents is carried out by the use of aWerner complex of the general formula MA X in which M is a metal ofatomic number above 12, A is a polyatomic anion and X is a heterocyclicnitrogen base, the nitrogen being part of the aromatic nucleus such as4-methylpyridine and 4'ethylpyridine. Using said Werner complexes, theclathration can be effected by three different methods, (1) directly bysimple contact between the aromatic compound to be clathrated and thesolid Werner complex, (2) by precipitation from a solution containingthe complex and the aromatic compound to be clathrated, or (3) by thepreparationof the Werner complex from its chemical components in thepresence of the aromatic compound to be clathrated. The clathratingcapacity of a Werner complex including a heterocyclic nitrogen base isbetween 5 and 70% of its own weight of a clathratable mixture.

To recover the clathrated component, the decomposition of the clathratecan be carried out in many ways, for example by heating, byacidification or by dissolving the clathrate in an appropriate solvent.If the decomposition is brought about by heating, however, it isdiificult to avoid decomposition of the Werner complex. In order to keepthe extent of such decomposition low it is amass Fatented Apr. 6, I965ice convenient to carry out the heating in an atmosphere of the nitrogenbase, but this in turn adversely aifects the equilibrium of thedissociation of the Werner complex in such a way as to repress thedissociation of the clathrate.

The object of the present invention is to provide a novel processemploying novel clathration agents.

Other objects and advantages of the present invention will becomeapparent upon further study of the specification and the appendedclaims.

With respect to the attached drawings, FIGURES l, 2 and 3 depict therelationship of temperature versus the degree of dissociation of variousclathration agents.

According to the present invention, the process of clathration comprisescontacting a Werner complex of general formula NiA X with one or morecompounds which are clathratable by said Werner complex, said Wernercomplex having been formed from a Werner com plex of general formula NiAX in the presence of said clathrtable compound or compounds, A being apolyatomic monovalent anion including a carbon atom doubly or triplybonded to a nitrogen atom, X being a primary phenyl-substitutedalkylamine, the phenyl group being either substituted or unsubstituted,the alkyl chain thereof containing from one to thirty carbon atoms.

According to another feature of the invention a process of forming aclathrate comprises contacting with a Werner complex of general formulaNi(SCN) X one or more compounds clathratable by said Werner complex,said Werner complex having been formed from a Werner complex of generalformula Ni(SCN) X in the presence of the said clathratable compound orcompounds, X being a primary, phenyl-substituted alkylamine, the phenylgroup being itself either substituted or unsubstituted and the alkylchain containing 1 to 30 carbon atoms. In the Werner complex of generalformula Ni(SCN) X at least one of the four molecules of combinedprimary, phenylsubstituted alkylamine may be different from the others.It is also to be noted that no choice is made regarding the form of thethiocyanate anion. The formula SCN must be taken as a whole and notrestricted specifically to the normal or iso forms.

Conveniently, a process of forming a clathrate consisting of a Wernercomplex of general formula Ni(SCN) X and one or more compoundsclathratable by Werner complex comprises contacting a mixture ofcompounds including said clathratable compound or compounds with aWerner complex of general formula Ni(SCN) X and adding to said contactedmixture the primary, phenyl-substituted alkylamine.

Alternatively, such a process comprises adding a Werner complex ofgeneral formula Ni(SCN) X to a mixture including said clathratablecompound or compounds and said primary phenyl-substituted alkylamine.

In addition, a process is provided of forming a clathrate consisting ofa Werner complex of general formula Ni(SCN) X and one or more compoundsclathratable by said Werner complex, in which the Werner complex ofgeneral formula Ni(SCN) X is prepared by heating a Werner complex ofgeneral formula Ni(SCN) X which is incapable per se of clathrating, withone or more clathratable compounds to a temperature sufiicient to bringabout complete dissociation of the said Werner complex into Ni(SCN) Xand 2X, and then cooling to effect recombination of the dissociatedcomponents to form a clathrate consisting of Ni(SCN) X and saidclathratable compound or compounds.

The invention further comprehends a process of resolving a mixture ofaromatic organic compounds which mixture contains at least one compoundclathratable by 2. Werner complex of general formula Ni(SCN) X.,, saidprocess comprising forming a clathrate with the clathratable compound orcompounds in said mixture by any of the methods hereinbefore described,and dissociating said clathrate in order to obtain the clathratedaromatic organic compound or compounds.

Conveniently the dissociation of the clathrate is effected by heating.Alternatively this dissociation may be effected by treatment of theclathrate with a mineral acid which does not react with the clathratedcompound or compounds, or by treatment with heated water vapor, or byelution with an inert solvent.

This invention further comprehends a composition of matter, being. a'clathrate, consisting of a Werner complex of general formula Ni(SCN) XX being a primary, phenyl-substituted alkylamine, the phenyl group beingitself further substituted or not further substituted, and the alkylchain conaining from 1 to 30 carbon atoms, and one or more aromaticcompounds. The invention also comprehends such a composition of matterwhenever produced by the process described herein.

The amine radical of the said primary phenyl-substituted alkylamine isadvantageously located on the terminal carbon atom of the alkyl chainand in LX-pOSitiOn with respect to the phenyl group.

A preferred amine according to the invention is a-phenylethylamine. Thefurther substituent, if any, which is attached to the phenyl group maybe hydrocarbon or not hydrocarbon provided that it does not interferewith the function of the amine radical.

In general, the alkyl chain, which may be straight or branched,preferably contains from 1 to 10 carbon atoms (and even more preferablyfrom about 1 to 8 carbon atoms); with more than 10 carbon atoms theclathration becomes increasingly difficult due to the increasingsolubility of the corresponding 4-base complexes in aromatic compounds.For steric reasons, when there is a branch ing on the alkyl chain, thetertiary carbon atom is preferably separated from the carbon atomcarrying both the amino and phenyl group by at least one methylenegroup.

The amines preferably conform to the following formula:

c wherein 1 R is either hydrogen or a primary alkyl group of preferably1-9 carbon atoms. f

R is the phenyl group, being unsubstituted, mono-substi tuted, orpoly-substituted.

If R is hydrogen, the phenyl group is preferably substituted. Ingeneral, when the phenyl group is itself substituted, the moietiesattached thereto affect to some degree the overall properties of thecomplex. Consequently, as a convenient breakdown, the complexes aredescribed as unsubstituted, mono-substituted and poly-substituted,referring to the degree of substitution of the phenyl group of theamine.

Unsubstituted.-In this case R is never hydrogen, and is preferably of1-9 carbon atoms.

Mn0substituted.-In this case R is preferably, of 1-9 carbon atoms and Ris a phenyl group of the formula YC H wherein Y is attached to a nuclearcarbon and is selected from the group consisting of an alkyl group of1-9 carbon atoms, and a polar group chemically substantially neutral toNH 7 It is, furthermore, preferred that Yand R do not eachsimultaneously contain more than 3 carbon atoms.

Polysubstit'uted.-Under this classification, the phenyl group issubstituted by alkyl groups on the one hand and by halogen groups on theother hand, as follows:

Alkyl-substituted.-In this type of oc-arylalkylamine, R is eitherhydrogen or a primary alkyl group, and R is a phenyl group substitutedby Z'to 3 alkyl groups at the 3,4,5 positions.

Because of steric effect and solubility considerations, it is preferredthat there be about 1 to about 6- carbon high selectivities andextremely high capacities as clathrating agents towards aromaticmolecules carrying at least one polar group such as ahalogen, a nitro,acyano, or even a hydroxyl group. .They form therefore a convenientmeans for extracting or resolving into their isomers molecules such as:

benzotrifluoride nitrobenzene nitrotoluenes dichlorobenzenestrichlorobenzenes cresols benzonitrile This list is by no meanslimitative and many other aromatic molecules are alsoclathrated.

When compared to complexes of the same general formula but using othertypes of arylalklyamines, the complexes used in this invention exhibitmarked and highly unexpected superiority in such clathration processes.

Hal0gen-substituted..ln this type of a-arylalkylarnine, R is againeither hydrogen or a primary alkyl group, and R is a3,4-dihalophenylgroup. The halogen substituents can be different orpreferably the same, being for example chlorine, bromine, iodine, orfluorine. The preferred group is 3,4-dichlorophenyl.

Because of solubility and steric effects, it is preferred that R containabout 1-9, more preferably 1-6 carbon atoms.

Complexes based on these amines are unexpectedly superior when used inclathration processes. They also have the advantage of being lesssoluble and generally less dissociated in aromatic vcompoundsthan thesimilar complexes not having two halogen substituents.

The following list, which is intended for purposes of illustration only,gives some examples of amines within the scope of the invention.

Para-methylbenzylamine u-Phenylethylamine a-Phenylpropylamineu-Phenylbutylamine a-Phenylamylamine ot-Phenylisoamylamine o-Phenylhexylamine a-Phenylisohexylamine dt-Phenylhe'ptylaminea-Phenyloctylamine ot-Phenylnonyl amine a-Phenyldecylaminea-Phenyloctadecylamine d- (Ortho-tolyl) ethylamine oc- Meta-tolyl)ethylamine a- (para-tolyl ethylamine oc- (Para-ethylphenyl ethylamineoz- (Para-cumyl) ethylamine Ot- (Paraeter-butylphe'nyl) ethylamine oc-(Para-nonylphenyl) ethylamine a- (Para-tolyl) butylamine a- Para-tolyl)hepthylamine Para-oromobenz'ylamine Para-dimethylaminobenzylamine w(Para-fluorophenyl) ethylamine I OL- (Ortho-chlorophenyl ethylamine ec-(Para-chlorophenyl ethylamine a- Meta-bromophenyl) ethylamine ot-(Para-bromophenyl) ethyl amine a-(Para-iodophenyl)ethylaminea-(Para-chlorophenyl)propylamine a- Meta-bromophenyl propylaminea-(Para-bromophenyl)propylamine oc- (Para-bromophenyl) butylamine a-Para-chlorophenyl) amylamine w Para-bromophenyl) amylamineot-(Para-fluorophenyl)isoamylamine OL- (Para-chlorophenyl isoamylaminea- Para-bromophenyl isoamylamine oc- (Para-chlorophenyl) hexylamineu-(Para-bromophenyl)hexylamine a-(Meta-bromophenyl)heptylamineu-(Para-bromophenyl)heptylamine zx- (Para-bromophenyl) nonylamine a-(Para-methoxyphenyl) ethylamine a Para-butoxyphenyl) ethylamine ot-Meta-nitrophenyl) ethylamine oc- 3 ,4-dimethylphenyl) ethylaminezx-(3,4-dimethylphenyl)butylamine w 3 ,4-dimethylphenyl heptylamine a- 3,5 -dimethylphenyl) ethylamine OL- (3 ,4,5trimethylphenyl) ethylamineCt- 3 ,4,5-trimethylphenyl) propylamine u- 3,4,5-triethylphenyl)ethylamine a- (3 ,4-dichlorophenyl) ethylamineot(3,4-dichlorophenyl)butylamine a-(3,4-dichlorophenyl)heptylamine O6-(3 ,4-dibrornophenyl ethylamine This list is given by way of example,and numerous other amines have been employed which have either differentalkyl chains or different substituents in the aromatic nucleus and arecapable of forming the 4-base complex and clathrates according to theprocess described herein. Different amines produce complexes whichclathrate to different extents and these different complexes dififer inthe particular compounds which they clathrate selectively. The choice ofamine is thus dictated by the particular conditions of the clathrationto be effected.

, All of the amines used in the compounds according to the presentinvention have a weak ammoniacal odor and thus differ markedly in thisrespect from the heterocyclic bases used in the known processes, whichhave a strong persistent nauseous odor. They also have a low vaporpressure thus reducing risk of fire or of inhalation of the vapor. Forexample y-picoline and 4-ethylpyridine are two of the heterocyclic basesmost used in the known processes of clathration, and the only ones whichform complexes which compare with the complexes according to the presentinvention as far as clathrating capacity is concerned. The boilingpoints of 'y-picoline and 4-ethylpyridine are 134 C. and 166 C.,respectively, whereas even unsubstituted benzylamine, which may beconsidered as the lower limit of the class of amines used in the presentinvention, has a boiling point of about 184 C. In any event the aminesin the compounds of this invention are less hazardous and less noxiousthan previously used heterocyclic bases, and from this standpoint,interalia, the compounds of this invention are markedly improved overthe prior art.

In addition, the amines used in the present invention are easy to obtainby Friedel-Crafts synthesis from benzene or a substituted benzene and anacid chloride and subsequent ammoniacal reduction of the intermediateketone.

The complexes formed with these amines are of two forms: Ni(SCN) X andNi(SCN) X The first of these forms Ni(SCN) X does not form anyvclathrate with aromatic organic compounds. It is, however, possible toobtain clathrates using the second form of complex Ni(SCN) X but inorder to bring about clathration using this complex it is essential tostart from the complex Ni(SCN) X and to convert it into Ni(SCN) X in the'6 presence of the compound to be clathrated. It appears that thistransformation leads to a specific arrangement of the crystal latticewhich is necessary to enable the host structure to include the secondconstituent of the clathrate. A point in favor of this theory is that ifone succeeds in removing a clathrated compound from a clathrate withoutdestroying the crystal lattice of the host compound it is possible toreclathrate this formerly clathrated compound by simple contact with thecomplex. A 4-base complex prepared in the absence of clathratablecompounds is however incapable of effecting clathration by simplecontact.

Experiments show that it is possible to bring about clathration by usingcomposite complexes of the type Ni(SCN) X -,X' in which X isphenyl-substituted primary alkylamine difierent from X but conforming tothe foregoing general definition. For instance, clathrates using suchcomplexes are easily prepared from the complex Ni(SCN) X to which 2molar equivalents of X are added in the presence of the compound to beclat'nrated. It is also possible to bring about clathrati-ons withcomplexes containing variable proportions of 2 or more amines conformingto the general definition. The use of such complexes is the scope of thepresent invention.

The solubility of the complex in hydrocarbons depends on the number ofcarbon atoms in the alkyl chain and on the nature of the substituents inthe aromatic nucleus. In general, the 2-base complex is less solublethan the corresponding 4-base complex. Preparation of these complexeshas been described in United Kingdom patent applications Nos. 38,654/58and 33,987/59. The composition of the clathrates is related to thestructure of the complex and to the composition of the mixture subjectedto clathration. In this respect there is a great difference between theprocess according to the present invention and that described in UnitedKingdom Patent No. 811,137. For instance, clathration of a mixture ofthe three o menes using a complex described in Patent No. 811,137, e.g.[NKSCNh (4-methyl pyridine) results in enrichment of p-cymeue in theclathrate. However, if the same mixture is treated with the complex[Ni(SCN) (ct-phenylethylamineh] according to the present invention,clath ration results unexpectedly in a strong enrichment of ocymenc.This phenomenon will appear clearly in the ensuing examples.

The nature of the substituent in the aromatic nucleus, and the length ofthe alkyl chain, also have an influence on what may be called theselectivity of the Werner complex in resolving mixtures. As in the caseof Werner complexes described by Schaeffer in United Kingdom Patent No.811,137, although broad tendencies may appear sometimes to indicaterules of selectivity, it is impossible, in the present state ofknowledge of the function of these compounds in the clathrating process,to predict specific examples of this selectivity.

It is essential, when performing clathration using Werner complexaccording to the present invention, that the complex shall pass from oneform to another in the presence of the mixture to be clathrated. It isnecessary that the complex shall pass from the form Ni(SCN) X to theform Ni(SCN) X in the presence of the mixture to be clathrated, and thisconversion can be brought about in a number of ways.

1 For a more thorough comprehension of the process which will bedescribed hereinafter, it is useful to consider the conditions whichaffect the equilibrium between these two forms of the complex. Theconversion of one form to the other is represented by the reaction whereX is an amine as previously defined. If this reaction between a solidand a liquid to produce another solid is carried out in a liquid mediumin which the amine is dissolved, it follows that the state ofequilibrium will depend on the nature of the liquid medium in which thereaction is carried out, and on the concentration of the amine dissolvedin this medium. Further, raising the temperature will displace theequilibrium toward the left, and, conversely, lowering the temperaturewill displace the equilibrium towards the right. For a given liquidphase, and operating at a given temperature, the equilibrium point ofthis reaction is determined solely by the concentration of the dissolvedamine. In effect, the equilibrium constant of the reaction, K, is givenby the expression K:l/[X] It follows that the presence of excess aminewill repress the dissociation of the 4-base complex. At ordinarytemperatures, and if the liquid medium is relatively inert, as is thecase when a clathration is being performed, the equilibrium is stronglyin favor of conversion to the 4-base complex even if only thestoichiometric quantity of amine is used.

, Under the same conditions, but at 120 C., any of the 4-base complexesof the present invention will be completely disassociated, even inconcentrated solution, but at this temperature dissociation of the2-base complex is negligible. It is therefore simple todetermine experimentally, for a given liquid medium, the relation between thetemperature and the degree of dissociation of the 4-base complex, sincethis degree of dissociation can be conveniently measured by theconcentration of free amine coexisting with the two forms of thecomplex.

FIGURE 1 shows the relation existing between the degree of dissociationof the complex [(Ni(SCN) (ct-phenylethylamineh] and the temperature,measured by the concentration of free ot-phenylethylamine. Themeasurements were carried out in two solvents, heptane and o-xylene, Thecomplete correspondence between the results obtained from observationsmade while raising the temperature and those made while lowering thetemperature indicated that the reaction was perfectly reversible andthat'equilibriu'm was attained in each case. It can be seen also thatthe nature of the liquid medium, in this case heptane or o-xylene, hasan effect on the degree of dissociation.

Since the degree of dissociation can be expressed as a simple linearfunction of the temperature it is therefore a simple matter to determineby calculation the experimental conditions for obtaining any desireddegree of dissociation. For example, in order to obtain completedissociation of 250 g. of the complex [Ni(SCN) (aphenylethylamineh]suspended in 1 kg. of o-xylene it is sufiicient to heat the suspensionat a temperature of 58 C. At this temperature the whole of the 4-basecomplex is converted into the Z-base complex and the effect of stronger.heating is merely to accelerate the reaction. Similarly, if it isdesired to work at a lower temperature, e.g. 45 C., then in order tobring about complete dissociation of 250 g. of the complex it isnecessary to place the 250 g. of the complex in suspension in 2 kg. ofo-xylene.

From the preceding it follows that in order to form the 4-base complexfrom the corresponding 2-base com plex it is necessary in order toachieve completion of the reaction to operate in the presence of excessamine,

' and the extent of this excess will depend both on the temperature atwhich the reaction is carried out and on.

the nature and quantity of the solvent employed. For example, at 25 C.the complex [Ni(SCN) (a-phenylethylamine) is formed quantitatively fromthe stoichiometric quantities of amine and Z-base complex, usingo-xylene as the solvent, provided that the amine be present in solutionin the o-xylene a concentration of atleast 0.112 mole/kg. At C. thenecessary con-' ent in solid form throughout the dissociation reaction,or at the very least the concentration of dissolved complex must benegligible in comparison with the concentration of free amine; thiscondition is necessarily realized in cases where clathration ispossible. It follows also that, once the relationship between thetemperature at which the dissociation is carried out and the extent ofthis dissociation taking place in a specific clathratable mixture isestablished it is a simple matter to establish by calculation theoptimum conditions under which to perform the clathration.

To carry out clathration according to the present invention it ispossible to employ any of a number of different methods. Firstly, onecan contact the mixture to be clathrated with the 2-base complex and addto this suspension the stoichiometric quantity of amine, together withthat additional amount of amine which corresponds to the amount of aminepresent by virtue of the dissociation of the .4-base complex in thisparticular medium. The clathrate is formed rapidly and can be separatedby filtration or centrifugation. Alternatively, it is possible to mixthe amine with the mixture to be clathrated, since these are usuallyentirely miscible, and to add to this homogeneous phase the Z-basecomplex in solid form. The clathrate is formed rapidly as in thepreceding method.

A further means of carrying out the invention consists ofccontacting amixture to be clathrated with a quantity of 4-base complex which isincapable-per se of clathrating, heating this contacted mixture to atemperature sufficient to bring about complete dissociation of the4-base complex into the Z base complex and free amine, and then coolingthe mixture so heated to effect recombination of the dissociatedcomponents to form a clathrate consisting of the 4-base complex and theclathratable compounds in the mixture. If in carrying out this methodcomplete dissociation of the 4-base complex is not achieved, throughinsufiicient heating, the 4-base complex not dissociated will not onlyremain inactive as acathrating agent after cooling but will in mostcases inhibit the formation of'a clathrate by the. remaining re-formed4- base complex- This is evidence that the 4-base complex is normallyincapable per se of clathrating, and that in order to obtain a form ofthe complex which will clathrate it is indispensable, in accordance withthe presout process, that the Z-base complex should be in the presenceof the mixture to be clathrated before any conversion of the 2-basecomplex to. the 4-base complex occurs.

Further, it is not necessarythat the Z-basecomplex be introduced as suchintothe mixture to be clathrated, it being quite in accordance with theinvention, that the 2-base. complex be formed in situ from its chemicalcomponents. This will be demonstrated clearly in the examples. r

i The process of clathration according to the present inventioncan beapplied to the purification of a mixture which contains at least oneclathratable impurity, and also to the resolution of certain mixtures.In the latter case it is necessary to recover the organic compounds fromtheclathrate formed as a result of the process, and to separate themtherefrom. In order to carry out this separation it is possible to.dissociate the clathrate Without'destroying or changing the structure ofthe complex. if the temperature of dissociation of the clathrate and ofthe complex are sufliciently' widely separated. The clathratesobtained'by the process 01: the present inven-' tion are particularlyapplicable to thermal means of separation, since the temperature gapbetween their temperatures of dissociation and the temperaturesv ofdissociation of the corresponding complexes is appreciably largerthanthe corresponding gap encountered when carrying out clathration usingWerner complexes which This separation, however, can only be employed Qembody pyridinic bases. The temperatures of dissociation of theclathrates are also lower than those of the clathrates obtainedaccording to the previously known procedures and this reduces the extentof the heating operation.

By way of example, FIGURE 2 shows the eflr'ect of heating a clathrateformed between [Ni(SCN) (u-phenylethylamineh] and o-xylene. o-Xylenecommences to be evolved from the ciathrate at about 30 C., and the vaporpressure of the o-xylene so liberated reaches the value of the vaporpressure of the pure hydrocarbon at a temperature of 60 C., at whichtemperature the dissociation of the clathrate can therefore beconsidered complete. At this temperature, however, the dissociation ofthe Werner complex is negligible. In fact, it can be seen from the graphthat the vapor pressure of free a-phenylethylamine, which gives anindication of the extent of dissociation of the Werner complex, does notbecome measurable until a temperature of 65 C. In the region of 100 C.,however, it begins to increase rapidly and achieves the value of thevapor pressure of the pure amine at a temperature slightly below 130 C.,at which temperature therefore the dissociation of the 4-base complexinto the 2-base complex can be considered complete.

On the other hand, referring to the case of a clathrate formed between[Ni(SCN) (4-methylpyridine) and p-xylene, FIGURE 3 shows thedissociation of the clathrate and of the Werner complex to be virtuallysimultaneous; at temperatures above 80 C. similar quantities of base andof hydrocarbon are liberated, and even at 130 C. neither of thesedissociation reactions is complete.

Evidently, therefore, in carrying out clathration according to theprocess of the present invention, it will be possible to carry out athermal process of separation of clathrated compounds and Werner complexat a much lower temperature than has been possible in the known process;furthermore, the product obtained as a result of this process ofseparation will be contaminated with 1 far less of the Werner complexbase than has previously been the case. This will be demonstrated in theexamples Which follow. The other complexes and clathrates obtainedaccording to the present invention show a similar behavior in theirapplicability to thermal separation as that which formed the basis ofthe comparison between FIGURES 2 and 3.

It is not absolutely necessary to carry out the separation of clathratedcompounds by a thermal process; indeed, it is possible to removequantitatively any clathrated compound or compounds from a clathrate byelution with an inert solvent (for example, a saturated hydrocarbon) inwhich the Werner complex is substantially insoluble, operating at atemperature equal to or even lower than the temperature of formation ofthe clathrate. Here again the clathrates obtained by the process of thepresent invention dilfer markedly from those obtained from pyridinicbase complexes of the known processes in which it is always necessarytocarry out'the elution' of the clathrated compounds at a temperatureappreciably higher than the temperature of formation of the clathrate.

Saturated hydrocarbons such as pentane, heptane or cyclohexane areperfectly suitable for carrying out such an elution, the Wernercomplexes obtained according to the present invention being insoluble,and furthermore undergoing only very slight dissociation to thecorresponding 2-base complexes, in saturated hydrocarbons. From thematter hereinbefore set forth, it is evident that elution of clathratedsubstances by means of an inert saturated hydrocarbon can be carried outWithout any dissociation of the 4-base complex provided that a quantityof amine corresponding at least to the equilibrium concentration of freeamine is added beforehand to the elution solvent. At room temperaturethis quantity of amine is generally very small compared with thequantity of destroy, the clathrates.

elution solvent, or even with the quantity of clathrated substances, dueto the much higher and faster dissociation of clathrates to thecorresponding 4-base complexes compared to the dissociation of 4-basecomplexes to the corresponding Z-base complexes. The different aspectsof this elution method will appear more clearly in examples.

The decomposition of the clathrates can also be carried out chemically.If an acid is used as the chemical means the base component of theWerner complex goes into solution as a salt of this acid and is usuallytherefore easily separated from the clathrated compound.

On the other hand, when carrying out thermal decomposition of theclathrate the clathrated compound will inevitably be contaminated withthe base forming the Werner complex, although this amount ofcontamination will be less using the process of the present inventionthan when using the previously known processes, as is shown by the vaporpressure curves in FIGURES 2 and 3, which compare clathration ofisomeric xylenes by the previously known process incorporating Wernercomplex in which the base is 4-met'hyl pyridine with clathration by theprocess of the present invention in which the base of the Werner complexis or-phenylethylamine. It is evidence that it is far easier to separatethe clathrated xylenes (B.P. 138144.4 C.) from a-phenylethylamine (RP.187.4" C.) than from 4-methylpyridine (B.P. l43.l (1.).

Similarly, the number of amines which are available is much greateraccording to the process of the present invention that has been the casein the prior art; furthermore, there is far greater scope for choosingan amine of boiling point Well separated from that of the clathratedcompound, this permitting good separation of the amine from theclathrated compound.

The resolution of mixtures containing at least one aromatic compound isanother application of the present invention. The mixture to be resolvedobviously must contain at least one clathratable compound. The processof clathration applied in such a case is identical to the process aspreviously described herein and will be further demonstrated in theexamples which follow. The compound clathrated selectively is thenseparated from the clathrate by chemical or physical means. A largenumber of mixtures have been resolved in this way and the efiicacy withwhich the separation is achieved will also appear in the examples.

In general, it is necessary to avoid the presence in mixtures to beclathrated of substances which are substituted by radicals which caninterfere with the action of, or Examples of such radicals are SO H,COOH, alkyl-NH and since these either react with the amine component ofthe Werner complex, or displace it from the complex.

In order that the present invention may be more clearly understood, thefollowing preferred specific embodiments of clathration according to theinvention are given, by way of examples, and are not intended to belimitative of the specification and appended claims.

(A) EXAMELES BASED ON UNSUBSTITUTED AND MONOSUBSTITUTED PHENYLALKYLA-MINE COMPLEXES Example 1 This example illustrates the preparation ofclathrates by the conversion of the 2-base complex into thecorresponding 4-base complex in the presence of a mixture to beclathrated. f-

The 2 base complex [Nl(sCN) (ot phenylethylamine) is first prepared fromits chemical components. a 39% aqueous solution of Ni(SCN) is obtainedby ll adding, to a solution of NiCl fiH O, 2 molar equivalents of KSCN.One volume of chloroform and two volumes of hepta-ne are added to thesolution of Ni(SCN) thus obtained, and to this Z-phase mixture there isadded, gradually and with agitation, two molar equivalents ofu-phenylethylamine dissolved in its own volume of chloroform. Theprecipitate formed is filtered off, washed once in suspension in a. 2/ 1heptane-water mixture, and Washed a second time in chloroform. It isthen dried under vacuum at 100 C. for several hours. The complexobtained is in the form of a pale green powder. No clathrate is formedby contacting an aromatic compound with this complex.

The use of chloroform in the above process is explained by its propertyof dissolving the 4-base complex but not the 2-base complex. Since, inaddition, chloroform decomposes most of the 4-base complexes of thepresent invention into the corresponding 2-base complexes, the latterare therefore obtained in the process of this example, in a state ofhigh purity and in practically quantitative yield.

To carry out clathration the 2-base complex is prepared as described andsuspended in about times its own weight of a mixture of oand m-xyleneand to this suspension there is added two molar equivalents ofu-phenylethylamine, plus a 14% excess of the total amine in order tobring about complete conversion of the 2-base complex to the 4-basecomplex. Very shortly after the addition of the amine there is a suddentransformation of the 2-base complex into the 4-base complex which ismarked by the appearance of a flocculent blue precipitate. Afteragitating the reaction mixture for about an hour the precipitate isfiltered, washed in the cold by suspension in heptane, dried for 2 hoursunder vacuum at room temperature, and decomposed by treatment with 6NHCl. The organic phase which separates from the acid phase is extractedwith cyclohexane and analyzed by infra-red spectrophotometry. Theresults obtained are set out in Table I.

TABLE I This example demonstrates how the clathration illustrated in theprevious example can be carried out by form ing the 2-base complex insitu from the 4-base complex, by heating the 4-base complex to above itstemperature of dissociation, in the presence of the compounds to beclathrated, and then cooling the completely dissociated 4-base complexto reform an undissociated 4-base complex which is capable ofclathrating.

A 30% solution of .Ni(SCN) is prepared as in the previous example andheptane is added to this solution. To the 2-phase mixture obtained isadded, gradually and with agitation, 4 molar equivalents ofu-phenylethylamine and an additional 121% excess of the amine in orderto ensure that only the 4-base complex is formed. The use of heptane inthis preparation is based on the fact that it has been establishedexperimentally the presence of 1 a liquid hydrocarbon results in a highdegree of purity of the 4-base complex so obtained. The precipitateformed is filtered and then washed in the same volumes of heptane andwater as were used in the previous example, and finally dried undervacuum, at room temperature, for several hours. The complex is obtainedin the form of a blue powder. The complex so obtained is not capable atordithe reaction mixture is cooled in running water.

1 is treated as in the previous example.

. l2. v nary temperatures of forming a clathrate upon simple contactwith a clathratable compound.

The complex [Ni(SCN) (a-phenylethylamine) so prepared is suspended inabout six times its weight of a mixture of oand m-xylene as in theprevious example. An excess of amine of 14% with respect .to the amountof ,amine present in the complex is added to this mixture in order toensure the formation of the 4-base complex only. The suspension is thenheated, with stirring, to a temperature of C. During the course of thisheating the 4-base complex is converted into the corresponding 2-basecomplex, this conversion being made apparent by a change in color of thesuspension'from blue to green. After maintaining the, reaction mixtureat a temperature of 125 C. for 30 minutes, the heating is'discontinued,and During the cooling the 2-base complex recombines with the amine toform the 4-base complex, this recombination occurring at a temperatureof about 40 C. and being accompanied by rapid color change of thesuspension from green to blue. When room temperature is attained, theprecipitate The results obtained are set out in Table I.

These results show that a clathrate prepared in accordanoe with theprocedure of Example 2 corresponds very closely in its composition to aclathrate prepared as in Example 1. Formation of a clathrate by theprocedure of Example 2, however, does not occur unless the reactionconditions are such that the 4-base complex is at some stage of theheating completely dissociated. If this dissociation is incomplete,either because the temperature to which the mixture is heated is toolow, or because the reactionis not continued for a sufiiciently longperiod; there will be obtained upon cooling mostly a 4-base complexwhich is not in the form of a clathrate.

Example 3 To a 15% solution of Ni(SCN) prepared from NiCl .6H O and twomolar equivalents. of KSCN are added, gradually and with stirring,'fourmolar equivalents of a-phenylethylamine, plus a 12% excess of the amineto ensure formation of only the 4-base complex. The added amine isdiluted in five times itsown volume of the mixture of xylenes used inthe previous-example.

Immediately on commencement of; the addition of amine a greenishprecipitate starts to form, and is identifiable as the 2-base complex.This precipitation, is completed at the end of the addition of the firsttwo equivalents of the amine, and analysis shows that it is quite freeof hydrocarbons and corresponds closely'to the formula[Ni(SCN)g(ot-phenylethylamine) During the addition of the remainder ofthe amine the precipitate turns blue, and also thickens considerably.After stirring for about 20 minutes, the precipitate is filtered andtreated as in the previous examples; Table I shows that'it consists of aclathrate which is identical in composition with those obtained inExamples 1 and 2.' If, however, in the present example the mixture ofhydrocarbons is introduced after the. formation of the 4-base complex,instead of with the amine, no clathration occurs.

This example also shows how the clathration illustrated in the previousexamplescan be carried .out as a single Example 4 An approximatelyequimolecular mixture of the three xylenes was clathrated by differenttypes of Werner complex by the process according to the presentinvention.

The clathration process employed was the same as that described inExample 3, but it was in certain cases necessition to 14 ion shown in'IIable 111 (similar in compo fractions obtained in the catalyticreforming of naphtha) using as the clathrating agent a number ion wasmade purely arbitrarily, for purposes of sary, in order to obtain aclathrate, to operate at a temposit perature below room temperature (0to 15 C.). Furthermore, the drying under vacuum was generally rewasclathrated placed by an additional washing in pentane, the clathrate ofdifferent Werner complexes according to the inven- Was then dried inair. The results obtained are set out in 5 tion. The choice of theparticular complex to effect this Table 11. These results show that theselectivity of the solut various illustration, and it is to beunderstood that other complexes of the same type are capable ofobtaining the same, or better, results. However, it is apparent from theing to the particular amine which is used to form the Werner complex,one can obtain an enrichment of diilerent components of the mixture tobe re Werner complexes in the clathration process varies bothquantitatively and qualitatively with the nature of the amine whichforms part of the complex, and that it is therefore possible to choose,for any particular clathra- 10 results that accord tion operation, thatamine which results in the isolation of a desired component of themixture.

TABLE II me 6m a l a t Ga 9 S 9 m Q m m ea aammm a a aaaaaa m a m o aa ao mw fritttrm rumtmfrrfrf t I t m .Etm. t m m 06 aarrtr a eaflaaflafi Ia r. r. MT 9 r 2 m PPOOOO POMPPPPPPP O P 0 0 M10 M 0 P 108338 59013758337 5 3 7 00 02 8 06 1 696645215867538507 3485803926 9 8 9 4 Sh n 5 1 m NMMH HH $W$ wuwwfifiwmww 9 m 8 3 WWE W M .m m P y M N% BNW%WM%NU m MB B mmW%% 2%% H mm 6 H %M% M m m n h W m 93982699746170 M0142 2373251899 9 9 55 135 0 9 l m C mwfiwww M%%%% WH M w %%W 7 m w u w. X 88865 2332430967888 0408870780 0 1 4 4 010 4 M 41 49 L5 .LLL A 1 4 2 2 O 4-5 2 42 2 4 4 4 2 t m 33d53333 330033333n n 3 3 3 3 Q0 3 3 H m 111297991199mfiillll 9794419149 9 6 3 7 969 9d 4 D 0 L1 1 L LLLQLQLI 1 3 3 1 1 3 3 1t U5 3333 339U33333Qu90 3 3 3 3 33 3 3 h n .m m S d iAmQ. 77 4 4 5 id4fl4ni4 4 4 4 R 4 4 4 4 5" 333 u 33 3333333n u33 3 3 3 3 3 3 w "II III:n .1: "I a e me e 3 331% m. h w m .1 .1 1 m mm iii j inmrwm m im a um mmX let .1 I VZ. yfl V. 1 2 e m. y v. hm E Xx n V. e n e o m i h imhm m flumm ee 0 h N e n e .mi mv. m ne me) baa hh n t n mni na e 1 m )1) l \1\/)l )v. e C mi m l l m m Q1 l a ly l l 1 11.11 1 1 11 1 i mw mammimmmmmwmmflwm wmww wnwbw n m wwwwwfifwwn m W m. .1 h m mhm xflahwhfiyyn mpmw m mm0Mm e mw me weememmmemenem c mv m N w hmm mw a h iaa mma hhwma ma au h a h t t e 6 w .Qbh 0 0 0 .n X D. n rum eoe oefl D u 1))000 OhOmmOMOOOD O 0 O0 010 n .1 epbamhmhondoDD vllrrrmm m m m rarunar m nnn 111Y 0 0a a a O 0 l h f X wwmmmm wmmmmm m wmmm wwmmmm mmnn wwwmmm mmmwmmmwmmma m 1 i l 1 i 1 eeeeeeeeeee T TncwmNTTFochBmo h B BOBFQC asaohhmnmeM h hhhhhhhhhhhhnw ..D.in rm.. .m.U-W1mmw mp.. m i.hm retireeoorlooooooioi i o hoe o o ooio oo i aaanaaauaaa aaaaa aaaaaaaaawca aaaaa a a mam a aa a Isomer (s) selectively elathrated .3 Para.

5.0 18.9 Para.

ly lead to a pronounced enrichment of a particular component of themixtur clathrated. Furthermore, repeated clathrations can obvious X inNi(SCN) X4 C *=1 ercent by weight of clathrated hydrocarbon in the,clathrate.

C,,*=percent by weight of elathrated xylenes in the clathrate.

Example 5 Under the same conditions as in the previous example,

a mixture of Xylenes and ethylbenzene, having the coma-phenylethylamlnea-phenylpropylamine a-(p-tolyDethylamine.--

a(p-bromophenyl)ethylamine 15 Example 6 A mixture of the threechlorotoluenes was clathrated by a number of the Werner complexes of thepresent invention. The procedure was the same as that employed inclathrating the mixture of xylenes in Example 4. The results are set outin Table IV. These results show that 16 40% of this isomer, such as isobtained in the reaction between toluene and isopropanol in the presenceof chlorosulphonic acid, it is possible in a small number of successiveclathration operations, for example two or three when using the complex1 [Ni(SCN) (ot-phenylethylamine) to obtain o-cymene in a state of highpurity.

TABLE V Weight percent of cymenes (o-, mp-) in Isomer (s) X in Ni(SCN)iX4 I O selectively clathrated Starting mixture Clathrated mixturea-Phenylethylamine 41. 0 2o. 6 3s. 4 91. 7 s. 7 1. s 10.8 Ortho.a-Phenylpropylaminm 24. 9 35. 6 39. 5 62.8 33. 2 4. 0 13. 1 Ortho.a-(p-Toiyl)ethylamine 31. 6 32. 0 36. 4 56. 6 17. 5 25. 9 19.8 Ortho. a-(p-Fluorophenyl) ethylamine 24. 9 35. 6 39. 5 57. 8 28. 5 13. 7. 12. 2Ortho. a-(m-Bromophenyl)ethylamlne 33. 6 35. 5 30. 9 6. 2 l3. 9 79; 9v11.8 Para. a-(p-Bromophenyl)butylamine. 24. 9 35.6 39. 5 28. 6 55. 8 15.6 21. 5 Meta 0rtho. a-gii-rlliluorophenybisoamyla- 33. 6 35. 5 30. 9 80.9 l7. 7 1. 4 13. 1 Ortho.

e. a-(p-Chlorophcnyl)isoamyla- 33. 6 35. 5 30. 9 87. 6 9. 4 3. 1 13. 6Ortho.

mine.

a-(p-Bromophenyl)heptylamine. 33. 6 35. 5 30.9 72. 7 18. 5 8. 8 12. 7Ortho. a-(m-Nitrophenyl)ethylamine- 33. 6 35. 5 30. 9 8. 3 21. 1 70. 67. 5 Para.

O *=pcrcent by weight of clathrated cymcnes in the clathrate.

Example 8 Table VI shows the results obtained by applying the procedureof the previous examples to the resolution of a mixture of aand[3-methylnaphthalenes. These hydrocarbons are frequently obtained intheform of a mixture TABLE IV Weight percent of chlorotoluenes (0-, m-, p-)in- Isomer (s) X in Ni(SCN)2 X4 0,. selectively clathrated Startingmixture Clathrated mixture a-Phenylethylamine 35. 0 29. 8 35. 2 45. 524. 1 30. 4 13. 1 Ortho. a-Phenylpropylamine. 35. 0 29. 8 35. 2 19. 825. 7 54. 5 14. 8 Para. a-Phenylbutylamine 34. 9 31. 6 33. 5 19. 2 10. 170. 7 11. 9 Para. a-Phenylamylamine- 35. O 29. 8 35. 2 75. 8 15. 2 9. 013. 4 Ortho. a-Phenylhexylarmne 33. 4 32. 2 34. 4 9. 5 67. 6 22. 9 11. 7Meta a-(p-Tolybethylamm 35.0 29. 8 35.2 62. 5 11. 4 26. 1 11. 5 Ortho.a-(m-Bromophenybethyl mine 32.8 32.3 34.9 7. 6 9. 1 83.3 12. 2 Para.a-(m- Bromophenyl)propy1-' 32. 8 32. 3 34. 9 75. 7 14. 4 9. 9 10. 6Ortho.

amine. a-(p-Bromophenyl)hutylarnine 34. 9 31. 6 33. 5 56. 7 30. 2 13. 18. 5 Ortho. wqgromophenylhsoamyl- 32.8 32. 3 34. 9. 78. 2 15. 1 6. 7 12.0 Ortho.

a ne. a-(m-Nitrophenyl)ethylamine. 33. 4 32. 2 34. 4 16. 9 14. 1 69. 08. 1 Para.

C$=Percent by weight of chiorotoluenes in the clathrate.

Example 7 A mixture of the three isomeric cymenes was clathrated by anumber of'the Werner complexes of the present invention. The procedurewas the same as that employed in clathrating the mixture of xylenes inExample 4. The results obtained are set outin Table V from which it isevident that the ortho-isorrner is generally clathrated from thedistillation of coal tar, or from the distillation of aromatic petroleumfractions. However, for certain applications, for example the synthesisof particular compounds, it is necessary to have one of the isomers inthe pure state. The results set out in. Table VI show that it ispossible, using one-of the mixtures obtained as a commercial product, toisolate one or other of the Selectively. Starting from a mixturecontaining about 7 isomers by clathration according to the process ofthe present invention and an appropriate choice of the recently claimedto be a possible substitute for dime-thyl- Werner complex. terephthalatein making polyester fibers and films.

TABLE VI Wei ht percent of methylnap thalenes (04-, fi-) in- Isomer X inN1(SCN) X4 O selectively clathrated Starting Clathrated mixture mixturep-Methylbenzylamine- 55. 5 44. 5 84. 2 15. 8 14. 1 Alpha.a-Phenylethylamine. 55. 5 44. 5 70. 9 29. 1 22. 2 Alpha.-Phenylpropylamine- 55. 2 44.8 23. 1 76. 9 26. 5 Beta.a-Phenylbutylamine 55. 5 44. 5 23. 9 76. 1 16. 3 Beta.a-Phenylhexylamine. 55. 2 44. 8 17. 4 82. 6 13. 1 Beta.a-Phenylheptylamine 55. 2 44. 8 69. 3 30. 7 26. 1 Alpha.a-(m-Tolyl)ethylamine 55.2 44. 8 64. 2 35. 8 20. Alpha.a-(p-TolyDethylamine 55. 2 44. 8 72. 8 27. 2 19. 6 Alpha.a-(p-Ethylphenyl) ethyla- 55. 2 44. 8 82. 2 17.8 16. Alpha.

mine. a-(p-Cumyl)ethylamine 55. 2 44.8 82. 9 17. 1 18. 7 Alpha.a-(p-Tolyl) heptylamine. 55. 2 44. 8 72. 8 27. 2 20. 8 Alpha.p-Bromobenzylamine 55. 5 44. 5 56. 7 43. 3 7. 6 a-giiOhlorophenyl)ethyla- 55.5 44.5 46. 8 53. 2 29.0 Beta.

ne. a-(n r-Bromophenyl) ethyla- 55. 2 44.8 1 76.9 17.3 Beta.

mine. a-(p-Bromophenyl) ethyla- 55. 5 44. 5 83. 7 16. 3 15,6 Alpha.

nnne. a-(p -Bromophenyl) isoamyla- 55. 2 44.8 80. 1 19. 9 12.0 Alpha.

mine. a-(p-Bromophenyl) heptyla- 55. 2 44.8 24. 5 75. 5 12. 7 Beta.

mine. 1 p-Dimethylaminobenzyla- 55. 5 44. 5 59. 4 40. 6 29. 3 Alpha.

IIIJHG. a-(p -Butoxyphenyl) ethyla- 55. 2 44. 8 42. 4 57. 6 l3. 1 Beta.

mine.

C,,*=Percent by weight of clathrated methylnaphthalenes in theclathrate.

Example 9 A mixture of 2,3- and 2,6-dimethylnaphthalenes was clathratedby a number of the Werner complexes of the present invention. Theprocedure was essentially the same as that employed for themethylnaphthalenes but all operations were performed at roomtemperature. Furthermore, in view of their high melting point thedirmethylnaphthalenes were dissolved in benzene for clathration.

TAB LE VII Example 10 muse-m (aapheny1ethylamine) The procedure was thesame as that employed in the preceding examples. The results show thewide variety The results are set out in Table VII. They of aromaticcompounds which may be clathrated by the Composition (in Relativepercent weight percent) (in Weight) of diot clathrated methylnaphthalene mixture (DMN, isomers (2,3-, 2.6-) X in Ni(SCN) X Benzene)0,,

Starting mixture Starting mixture DMN: 41.8; Benzene: 58.2 2.6-: 50.4

a-Phenylpropylamine 94. 4 5. 6 42. 2 57. 8 18. 2 a-Phenylbutylamine"86.8 13.2 33.2 66.8 18.2 a-Phenylhexylamine 74. 8 25. 2 35. l 64. 9 l0.1 a-(p-Bromophenyl)ethylamine 67. 3 32. 7 26. 4 73. 6 14. 7a-(p-Bromophenyl)butylamine 58. 0 42. 0 6. 4 93. 6 17. 9

O J =Percent by weight of clathrated hydrocarbons (dimethylnaphthalenesand benzene) 1n the clathrate.

thalenes are much better clathrated than benzenethough this is presentin high concentration in the starting mixture. 2,6-dimethylnaphthalenemay be used to produce dimethyl-naphthalene-2,6-dicarboxylate Which hasbeen forming to the invention would give still better results.

- ture.

present process and also the strong selectivities exhibited by thecomplex even with isomers of very similar struc- It must be noted thatthe choice of the complex was made arbitrarily. From the precedingtables, it is evident that for certain mixtures, other complexes con-TABLE VIII Composition (in mole percent) of- O t Starting materialClathrated mixture Propylbenzenes: 11-: 50.4; iso-: 49.6 20.3 79.7 10. 9Butylbenzenes: n-: 26.9; is-: 27.1 sec- 21.7;

ter-: 24.3 15. 8 17. 8 19. 6 46. 7 17. 1 Xylenes: See, Table I1.

Styrene: 47.9; Ethylbenzene: 52.1 79.0 21.0 16.9 Diethylbenzenes: o-:31.8; m-: 31.2; p-: 37.0- 92. 6 4. 2 3. 2 8. 6 Ethyltoluenes: 0-: 33.5;m-: 33.9; p-: 32.6 74.3 17.7 8.0 13.9 Cymenes: See Table V.

Ethylisopropylbenzenes: 0-: 23.7; m-: 20.0; p-:

55.7 79. 9. 13. 4 6. 7 9. 7 Cyclohexyltoluenes: 0-: 28.6; m-: 15.8; p-:55.6-. 85. 8 6. 7 7. 17. 5 Chlorotoluenes: o-: 35.0; 111-: 29.8; p-:35.2 45.5 24.1 30.4 13.1 Bromotoluenes: 0-: 32.9: m-: 32.5; p-: 34.6.68.6 14.4 17.0 23.5 Dichlorobenzenes: o-: 50.3; p-: 49.7 85.4 14.6 14.2Trimethylbenzenes: 1,2,3-: 34. 1,2,4-2 31.6

1,3.5-z 33.8- 3.0 17.8 o-Ethyltoluene: 51.2; Mesitylene: 48.8 1.8 13.9Dimethylethylbenzenes:

1,2-diMe,4-Et. 50.0 69.0 8.6 1,4-diMe, 2-Et.: 50.0

I 1,3-diMe,4-Et.: 50.0 82.0 10.3

1,4-diMe, 2-Et.: 50.0 1,3-diMe,2-Et.: 7.0 25.3 11.2 1,3-diMe, 4-Et.:54.3 1,3-diMe, 5-Et.: 38.7. Naphthalene: 32.6; Tetraline:- 34.1;Decaline:

33.3 84. 9 12. 9 2. 2 16. 2 Naphthalene: 50.0; diphenyle: 50.0 98.5 1.516.2 Methylnaphthalenes: See Table VI.

Ethylnaphthalenes: 11-: 49.1; 3-: 50.9 69.9 33.1 20.2

O *=Percent by weight of calthrated compounds in the clathrate.

Example 11 elution at a temperature not above the temperature of watervapor heated to a temperature of about 60 C.,

which passed through the column. At the outlet of this column the waterwas condensedand could ,be even-- tually recycled. The completeapparatus was maintained under reduced pressure, in the present exampleat a prescolumn the water vapor carried off the clathrated hydrocarbon,and on condensing this water vapor containing the free hydrocarbon, thehydrocarbon separated into a supernatant organic phase which was easilyseparable by decantation. During this process several fractions of 5 thecondensate were collected and analyzed for their content of water,o-xylene and amine. The results obformation of the clathrate and withoutdecomposition of the Werner complex with-which the clathrate has beenformed. 7

25.0 g. of a xylenes- [Ni(SCN) (a-phenylethylamine) clathrate, producedby clathrating a mixture of oand mxylene (30% and 70% respectively) areput in a vertical glass column. Hept'ane containing 0.1 mole ofet-phenylet'hylamine per'liter is slowly and continuously introduced atthe top of the column. At the bottom of V the column fractions arecollected at regular intervals and analyzed by vapor phasechromatography. The r'esults obtained are set out in Table X. Theseresults showthat it is possible to remove the whole of the clathratedxylenes by elution with an inert solvent at a sure of 30 mm. Hg. Duringits passage through h emperature not above that usedduringtheclathration process. The small quantity of amine added to the elutionsolvent completely suppresses the dissociation of the 4-base complex.Results show that in some cases the elution process brings 'about afurther separation of the clathrated compounds; in the present casefractions from 4 to 11 are richer in o-xylene than the mean compositionof clathrated xylenes.

This example illustrates one method by which aromatic compounds whichhave been clathrated by the process of any of the examples from 1 to 10can be recovered by tained are set out in Table IX. These results showthat TABLE X the Whole of the o-xylene was removed from the clath- 'ratein approximately one hour by approximately its Weight Percent by s ggiggg ge gp own weight of water. During the same period only 2% Fr ct o N0.the ac weight o Xylenesl of the amine forming part of the complex wasobtained ff figi g in the condensate. oin- TABLE 1X 4. 48 36.4 1 4o 4.24 24.6 49 51 o-Xylene removed Amine removed from 3. 27 21.3 55 45 fromclathrate complex 3.96 18.4 59 41. Time H20 4. 35 16. 5 60 40 (mins)used (g.) 4.83 10.1 63 37 Percent of Percent of 5. 00 8.8 61 39 G.total, o-xylene G. total amine 5. 11 6. 5 61 39 in clathrate in complex6. 36 3. 3 62 38 2% 3.0 61 3s 2.2 Meaneomposltionofthoclathratedx leneas shownb direct anal sis 11. 36 5. 48 0.533 2.7 of the clathrate: o-,57%; 111-, 43%. y h V y I 70 (B) EXAMPLES BASED ON POLYALKYLPH-ENYL-Example 12 ALKYLAMINE COMPLEXES p Example.]3

This example illustrates the separation of. p-dichloro- Z-l benzene outof its isomers by clathration with a polyalkylphenyl amine.

To a solution of Ni(SCN) prepared from NiCl .6H O

22 employing the same complex or other complexes according to theinvention; the results of such clathrations are summarized together withthe preceding results in Table XI.

TABLE XI Composition Olathrated Aminated base of the 4-base Compositionof the of the clathratcompounds in complex feed (moles percent) edmixture the clathrate (moles (weight percent) percent)a-(3.4-dimethylphenyl) ethyl- Diehlorohenzenes:

amine. 0-: 33 3 4 15. 7 93 a-(3,5-dimethylphenyl) ethylamine. 35

33 7. 7 32 V a-(3,4,5-trimethylphenyl) ethylamine. 39

5.1 p-: 34.-- V 31 Nitrotoluenes:

35 10. 1 30 23 Benzotrifiuoridez 77 8. 5 a-(3,4-dimethy1pheny1) buty1Diehlorobenzenes:

amine. o-z 32 36 m-: 34- 23 8.9 p-: 34 41 a-(3,4,5-triethylpheny1)ethyl- Dichlorobenzenes amine. 0-: 32

m-: 34..." 28 12.1 p-: 34"" 32 Nitrotoluenes:

o-: 32.- 39 m-: 35- 30 11. 2 p-: 33"-- 31 Toluene: 52 43 6.9Benzotrifluoride: 48". 57 a-(3,4-dirnethy1phenyl) butyl-Trichlorobenzenes:

amine. 18. 4

a-(BA-dimethylphenyl) hepty1 amine. 49

28 26. 1 27 a-(3,4,5-trimethy1pheny1) propylamine. 33

and 2 molar equivalents of KSCN it is gradually added, with stirring atthe ice bath temperature, 4 molar equivalents ofu-(3,4-dimethylphenyl)ethylamine plus a 12% excess of the amine in orderto ensure formation of only the 4-base complex. The added amine isdiluted in about three times its own volume of a mixture ofdichlorobenzenes (mole percent of isomers: a, 33; vm-, 33; p-, 34) andn-heptane (3/1 in volume). Heptane is used as solvent of thedichlorobenzenes in order to avoid precipitation of the para-isomer.After stirring the reaction mixture for 30 minutes, the resultingprecipitate is separated by filtration, washed twice in the cold bysuspension in heptane and in pentane and finally it is dried in the air.A 3 g. aliquot of the dry precipitate is decomposed by 10 ml. of 20%sulfuric acid. After decomposition, the sulfuric acid is diluted by 20ml. of distilled water and the clathrated diohlorobenzenes are extractedby 10 ml. of cyclohexane and analyzed by spectrophotometry. It is thusfound that 15.7 W. percent of the precipitate are diehlorobenzenes witha strong enrichment of the para isomer (in mole percent: 13-, 3; m-, 4;p-, 93). Further analysis of the precipitate shows that the remainderconsists essentially of the 4-base complex Other resolutions of mixturesof polar substituted aromatic compounds are realized by the sameprocedure Substantially the same results as those of Table XI areobtained by contacting any of the complexes [Ni(SCN) (amine) and themixture to be resolved; nevertheless, a simple contactting willgenerally not bring about the formation of the clathrate; it is thus anembodiment of of this invention to heat the mixture up to a temperatureat which all the complex [Ni(SCN (amine)4] is dissociated into thecomplex [Ni(SCN) (amine)z] and free amine, then cooling in order to formthe clathrate of the complex [Ni(SCN) (amine) with the clathratablearomatic compound. An alternative method for getting the same results isobviously to add to the mixture containing the complex [Ni(SCN) (arnine)and at least one clathratable aromatic compound two molar equivalents ofthe said amine thereby forming the clathrate of the complex [Ni(SCN)(amine) with the said clathratable aromatic compound. For both methodsit is convenient to add an excess of amine corresponding tothedissociation of the 4-base complex at the clathration temperature inorder to get a maximum capacity of clathration.

In Example 13 hereinabove, one uses a diluted acid in order to destroythe clathrate and to recover the clathrated compound; this destructivemethod is of course only suitable for analytical purpose; for industrialpurpose it ismore advantageous to use a method which does not destroythe 4-base complex'or at least the Z-base complex. This may be done byheating the'elathrate to a temperature at which it is destroyed but notthe complex. For instance, one can remove the clathrated compound out ofthe clathrate by steam stripping under reduced pres.- sure at atemperature such as the 4-base complex remains unaltered or at a highertemperature such as 2 molar equivalents of the amine are removedtogether with the clathrated compound leaving the complex '[Ni(SCN)raphy. For instance, if the clathrate is dispersed in an inert aliphaticsolvent such as heptane which may possibly contain a small amount ofamine corresponding to the dissociation of the 4-base complex, theclathrate will .loose its clathrated compound, leaving finally theunaltered complex [Ni(SCN) (amine) which is thus.

ready for a new clathration.

Those clathration and recovery processes using the new complexes willnow be described with reference to the following examples.

Example 14 own volume of n-heptane.

complex by heatingthe latter, in the presence ofthe compounds to beclathrated, at a temperature Sllfi'lClBIlt to bring about its completedissociation into the corresponding 2-base complex and free amine, andthen cooling the mixture to reform a 4-base complex which is capable ofclathrating.

The 4-base complex [Ni(SCN) {oc-(3,4-dimethylphenyl)ethylan1ine} isfirst-prepared from its chemical components. A 15% solution of Ni(SCN)is prepared as in the preceding examples and one half volume of nheptaneis added to this solution. To the biphasic mixture so obtained are thenadded, gradually and with stirring, .4 molar equivalents of the amineplus a 12% excess in order to ensure complete formation of the 4- basecomplex. The added amine is diluted in about its The use of heptane inthis preparation is justified byjthe. experimental fact that thepresence of a liquid hydrocarbon results in a higherde- This exampleillustrates the preparation of clathrates by the conversion of Z-bas'ecomplexes into the corresponding 4-base complexes in the presence of amixture to be clathrated.

The 2-base complex [Ni(SCN)g{u-(3,4-dimethylphenyl ethylamin h] is firstprepared from its chemical components. To a 15% solution of Ni(SCN)prepared fro'm NiCl eH O and 2 molar equivalents of KSCN are added onevolume of heptane and one half volume of chloroform. To the biphasicmixture thus obtained are then benzenes and heptane as in the previousexample. The

ratio complex/suspension medium is'chosen so that a fluid slurry isobtained (5 to 10 ml. of suspension medium 1 per gram of complex). Anexcess of amine of about 0.2

added gradually and with stirring, 2 molar equivalents ofa-(3,4-dimethylphenyl) ethylamine dissolved in about its own volume ofchloroform. After stirring the reaction mixture for 30 minutes, theprecipitate formed is filtered;

off, washed once by suspension in a 1/1' heptane-water mixture, Washed asecond time in chloroform and finally it is dried under vacuum at 100 C.for 2 hours. The complex obtained is in the form of a pale green powder.

The use of chloroformin the above process is justified by its propertyofdecomposing most of the 4-base complexes of the present invention intothe corresponding. 2-base complexes so that the latter are obtained,when chloroform is present, in a state of high purity;

To carry out the clathration, the complex [Ni(SCN), {a-(3,4-dimethylpheny1 ethylamineh] prepared as hereinbefore described issuspended at the ice bath temperature in about ten. times'its weight ofa mixture of dichlorobenvzenes (mole percent of isomers: 'o-, 31; m-,34; p-, 35)

and n-heptane (3/1 in volume). To that suspension are then added 2 molarequivalents of a-(3,4-dimethylphenyl) ethylamine plus an excesscorresponding to a finalconcentration of about 0.2 mole of free amineper liter of suspension medium for bringing about complete conversion,of the 2-base, complex intothe 4-base complex. This conversion occursshortly after the addition of the amine and it is made apparent by theformation of a blue precipitate. After agitating the reaction mixturefor.

about one hour, the precipitate is filtered off, washedtwice in, thecold by suspension in heptane andin pentane and finally it is driedin-the air at room temperature.

This example demonstrates how the clathration illus trated in theprevious example can be carried out by forming the 2-base complex; insitu" from the 4-base It is.

mole per liter of suspension medium is added to the system in order toensure the complete reformation of the 4-base complex. The suspensionisthen heated with stirring at a temperature of 95 C. During the .courseof this heating, the original blue complex is rapidly converted intothecorresponding Z-base complex which ap pears as a green precipitate.After one hour at 95 (3.,

the reaction mixture'is cooled at the ice bath temperature. By thiscooling, the 2-base complex recombines with free amine to form a 4-basecomplex, this transformation being made apparent by a rapid change, ofcolor of the suspension from green to blue.. After-maintaining thesuspension at about 0 C. for one hour, the resulting clathrate isfiltered off and treated as in the. preceding example.

The analysis shows that 13.4 Wt. percent of the dry clath cent: o-, 2;m-, 2; p-, 96).

Example 16 This example illustrates one .method by which aromaticcompounds clathrated ,by the process of any of the preceding examplescan be recovered'by elution with an inert solvent,,without decomposition'of, the Werner complex with which the clathrate has been formed.

10.0 g. of the clathrate prepared according to the previous example aresuspended at room temperature in 100 ml. of n-heptane containingdissolved free amine in the amount of 0.3 mole per, liter. in order'toavoid the dissociation of the 4-base complex. After stirringthe'suspension for about three hours, the precipitate is-filtered olf,washed with'cold pentane and dried in the air.

By decomposingan aliquot of the precipitate with rate are substantiallypure p-dichlorobenzenejmole per- H 8 0 20%, it-is madeevident that it isfree'of clathrated material, that is to say," that bythe above treatment the dichlorobenzenes have been completely removed from theclathrate. Further *analysis ofthe resulting precipitate shows itconsists of the pure 4-base complex.

.(c EXAMPLES BASED 'oN 3,4-DIHAL0PHENYL .ALKYLAMINE COMPLEXES I iExample '17 I This example illustrates the separation of para-diiso- 25propylbenzene out of its isomers by clathration with one of the newWerner complexes based on 3,4-dihalophenylalkylamines.Para-diisopropylbenzene in admixture with its isomers is found as aby-product of the synthesis of 26 complex [Ni(SCN) (amine) with theclathratable aromatic compound. An alternative method for getting thesame results is obviously to add to the mixture containing the complex[Ni(SCN) (amine) and at least one clathratable aromatic compound twomolar equivalents of the cumene. It is a valuable starting material forthe syn- 5 sald amine thereby forming the clathrate of the complexthesis of terephthahc acid. (SCN th 1 flu t M To a 15% solution ofNi(SCN) prepared from f t c )2 2 5 2 n 33 .5: i i i g NiC1 .6H O and 2molar equivalents of KSCN it is gradudd m 1 h f 11 added at the ice bathtemperature with stirring 4 a an excess 0 amme correspon mg.to t ebsoclatlqn a y of the 4-base complex at the clathratlon temperature inmolar equlvalents of oa-(3,4:d1chlorophenyl)butylamme Order to get amaximum capacity of clathratiom P a 12% excess of the amme m order toensum P In Example 17 hereinabove, one uses a diluted acid in h of y thef P The added amlhe order to destroy the clathrate and to recover theclathiS diluted in. about thre times Its 0WD Volume of thfi mlX- atedcompound: destructive method is of course ture of diisopropyl nz n to becla'lhrated 111016 only suitable for analytical purpose; for industrialpurpercent 0-, 12; m-, 29; p-, 59). After stirring the repose it is moreadvantageous to use a method which does action mixture for 30 minutes,the resulting precipitate not destroy the 4-base complex or at least the2-base comis separated by filtration, washed twice in the cold by plex.This may be done by heating the clathrate to a suspension in heptane andi pentane d finally it i temperature at which it is destroyed but notthe complex. dried in the air. A 3 g. aliquot of the dry precipitate is20 For Instance, one can remove thefikfthrated compound decomposed by 10m1 of 50% acetic acid After out of the clathrate by steam strippingunder reduced composition, the acetic acid is diluted by 20 ml. of disati fi the 4'base fiomplex tilled Water and the clathrated hydrocarbonsare extracted reniams g q temperature 3 t i O by 10 ml. of p-xylene andanalyzed by vapor phase chro- 9 ar equwa an S 0 e amme am .remove Gee ermate Ia h It is thus found that 143 w rcent of with the clathratedcompound leaving the complex th g l. 1b Pe [Ni(SCN) (amine) In bothcases the remaining Preclpl a e are HSQPmPY nzenes W1 a stfnng complexesare ready for a new clathration step by one r1chment of the para isomer(1n mole percent. 0 of the alternative methods given hereinabove.Another, 11; Further 311121131818 f the Preclpltate and even preferred,method of recovery of the clathrated Shows that h remainderessentlanydof 4'base compound without destruction of the 4-base complexis complex )2 h by elution with an inert solvent, much the same as inchro- Oth6r 1'eSO1ut1OnS of mlxtu-res of woman? compounds matography.For instance, if the clathrate is dispersed are Teahmd y the Same POcedure pmp y sfme in an inert aliphatic solvent such as heptane whichmay complex or other Complexes accordlhg t0 the lhvehhoh; possiblycontain a small amount of amine corresponding results of suchclathrations are summarized together with to (the dissociation f the pcomplex, the clathrate. the Preceding results in Table will loose itsclathrated compound, leaving finally the un- TABLE XII CompositionClathrated Ammated base of the 4-bsae Composition of the of theolathracompounds in complex feed (mole percent) ted mixture theclathrate (mole (weight percent) percent) 'a-(3,4dichloropheny1) ethyla-Cymenes:

mine. o=33 35 m=34 33 20.3 p=33--.. 32 a-(3,4-dichlorophenyl) butyla-'Ethylisopropyl benlIllIle. zenes:

5 20.9 a-(BA-dichIOmphenyI) heptylamine. 36

, l 9 12.1 a-(3,4-dibromophenyl) ethylamine; 41

Substantially the same results as those of Table XII are obtained bycontacting any of the complexes [Ni(SCN) (amine);] and the mixture to beresolved; nevertheless altered complex [Ni(SCN) (amine)4] which is thusready for a new clathration.

Those clathration and recovery processes using the new a simplecontacting will generally not bring about the 7 compiexes will now bedescribed with reference to the formation of the clathrate. It is thusan embodiment of this invention to heat the mixture up to a temperatureat which all the complex [Ni(SCN) (aminehl is dissociated into thecomplex [Ni(SCN) (amine)2] and free following examples.

, Exampla18 This example illustrates the preparation of clathratesamine, then cooling in order to form the clathrate of the 75 by theconversion of 2-base complexes into the correspondis added to thissolution.

ing 4-.base complexes in the presence of a mixture to be' clathrated.

The 2-,base complex [Ni(SCN) {a-(3,4dichlorophenyl)butylamine} is firstprepared from its chemical-components. To a 15% solution of Ni(SCN)prepared from NiCl .6H O and 2 molar equivalents of KSCN are added onevolume of heptane and one half volume of chloroform. To the biphasicmixture so obtained are then added, gradually and with stirring, 2 molarequivalents of u-(3,4-dichlorophenyl) butylamine dissolved in about itsown'volurne of chloroform. After stirring the reaction mixture for 30minutes, the precipitate formed is filtered off, washed once bysuspension in a 1/1 heptane-water mixture, Washed a second time inchloroform and finally it is dried under vacuum at 100 C. for 2 hours.The complex obtained is in the form of a pale green powder.

The use'of chloroform in the above process is justifiedisopropylbenzenes as in the previous example. complex/hydrocarbons ischosen so that a fluid slurry is obtained (5 to ml. of hydrocarbons pergram of complex). An excess of amine of about 0.2 mole per liter ofhydrocarbons is added to the. system inorder to ensure the completereformation of the 4-base complex. The suspension is then heated.with'stir-ring at a temperature of 95 C. During the course of thisheating, the original 1 room temperature.

. this transformation being made apparent by a rapid color by'itsproperty of decomposing most of the 4-base complexes of the presentinvention into the corresponding 2-base complexes so that the latter areobtained, when chloroform is present, in a state of high purity.

To carry out the clathration, the complex [Ni(SCN){a-(3,4-dichlorophenyl)butylamineh] prepared as hereinbefore describedis suspended in about 10 times itsown b 2-base complex into the 4-basecomplex. This conversion occurs shortly after the addition of the amineand it is rnade apparent by the formation of a blue precipitate. Afteragitating the reaction mixture for about one hour, the

precipitate is filtered off, washed twice in the cold by suspension inheptane and in pentane and finally it is dried in the air at roomtemperature. 7

The clathrate so obtained is treated and analyzed as in the precedingexample. its weight consist of diisopropylbenzenes substantiallyenriched in the para-isomer (in mole percent: o-, 6; m-., 16;, -p-, 78).

Example 19 This example demonstrates how the .clathration, illustratedin the previous example can be carried out by form.- a

ing the Z-base complex in situ from the -4-base complex by heating thelatter, in the presence of the compound to be clathrated, at atemperature suificientto bring about its complete dissociation into thecorresponding 2-base complex and free amine, and then cooling themixture to It is thusshown that 18.2% of reforma 4-base complex which iscapable of clathration.

I The 4-base complex [Ni(SCN) {a-(3,4-dichlorophenyl) butylaminfih] isfirst prepared from its chemical components. A 15 solution of Ni(SCN) isprepared as in the preceding examples and one half volume of n-heptaneTo the biphasic mixture so obtained are then added, gradually and withstirring, 4 molar equivalents of the amine plus a 12% excess in order toensure'complete formation of the 4-base comf plex. The added amine isdiluted in about its own volume of n-heptane. The ,use of heptane inthis preparation is justified by the experimental factthat the presenceof a liquid hydrocarbon results in a higher degree of purity of thecomplex so'obtained. In this example, the heptane used is distributedbetween the Ni(SCN) solution and the amine to be added butit may also.be entirely added with.

the amine.

Afterstir'ring for 30 minutes, the resulting precipitate is filteredofi, Washed by suspension in a 1/ 1 mixture hep-{oc-(3,4-dichlorophenyl)ethylamineh] prepared as here-' inabovedescribed is suspended in the-same mixture of di change of thesuspension from greento blue. After maintaining the suspension at roomtemperature for one hour, the resulting clathrate is filtered otf'andtreated as in the preceding examples. I p

The analysis shows that 17.9 w. percent .of the dry clathrate aredissopropylbenzenes stronglylenriched in the.

para-isomer (in mole percent: o-, 5; m-, 16; p-, 79).

Example'20 I This example illustrates one method by which aromaticcompounds clathrated by theprocess of any of the preceding examples canbe recovered by elution with an inert solvent, without decomposition ofthe Werner complex used in the clath ration step. Q x

g. of the clathrate prepared according to the previous example aresuspended atroom temperature, in 100 ml. of n-heptane containingdissolved amine in the amount of 0.1 mole per liter in order to avoidthe dissociation of the i -base complex. After stirring the suspensionfor about onehour, the precipitate isfiltered off, washed with coldpentane and dried in the air.

An aliquot of the dry precipitate is treated as in the precedingexamples for determining its content in hydrocarbons. It is thus foundthat 7.8% of its weight consist of almost pure p-diisopropylbenzene, (inmole percent: -o-, 0; m-, 6; p-, 94initially 79); One may thusestimatethat during the preceding treatment more than 60% of the clathratedhydrocarbons, have ,beenremoved-from the.

clathrate.

The remaining ofthe precipitate is suspended in a fresh elution mediumfor a further hour and the resulting precipitate analyzed as before; It.is now vfound that the latter consists ofthe pure 4-base complex. 7

Obviously, this two steps elutionl may'be effected in a continuousmanner, much as in chromatography. It must be noted thatwith otherclathrates, a complete elution may be effected in one singlestep,'depending on the coma 7 plex used andthe nature of the clathratedcompounds.

The preceding results also show thatinsome cases the elution processbrings abouta further, separation of the clathrated compounds; inthe'present' example it is'seen.

that the diisopropylbenzenes'desorbed by the second elution are muchricher in the para-isomer than are the original clathrated hydrocarbons.

From the foregoing descriptiomione skilled the art can readflyappreciate the essential characteristics, of the invention; Itisunderstood that without departing from the spirit and scope of theseessential characteristics, the inventionis susceptible to other1rnodifications in order to adapt it to various'usages and conditions,and accordingly such modifications should and are intendedtobe-comprehended'within the full range of equivalence of the followingclaims.

What is claimed is: I V

1. A process of resolving a mixture of'organic compounds, said mixtuneincluding an aromatic compound selected from the group :consisting ofbenzene," mono-, diand trialkylbenzenes wherein each alkyl radical hasno more than three'carb'on atoms, ring substituted monohaloderivativesof benzene and of -rnonoalkylbenzenes, dihalobenzenes, styrene,cyclohexyltoluenes, 'tetraline,

The ratio naphthalene, and monoand dialkylnaphthalenes wherein eachalkyl radical has no more than three carbon atoms, by clathration ofsaid aromatic compound with a Werner complex Ni(CNS) X wherein X is aprimary arylalkylamine of general formula:

wherein R is a primary alkyl radical of 1 to 6 carbon atoms and R is anaromatic radical selected from the group consisting of phenyl, mono,diand trialkylsubstitnted phenyl radicals wherein substitution occurs atany of the 3, 4 and 5 positions of said phenyl radical, said alkylsubstituents having each less than three carbon atoms, phenyl radicalssubstituted by a polar radical selected from the group consisting ofhalogen, nitro, alkoxy containing 1 to 5 carbon atoms andN,N-dialkylamino wherein the alkyl portions contain 1 to 2 carbon atoms,and 3,4-diahalophenyl radicals, said resolution comprising heating inthe presence of said mixture and Werner complex Ni(CNS) X in order todissociate said Werner complex into .the corresponding complex Ni(CNS) Xand 2 free moles of the amine X, then cooling thereby forming theclathrate of the Werner complex Ni(CNS) X with said aromatic compound,and recovering by known methods the selectively absorbed aromaticcompound without dissociation of the Werner complex Ni(CNS) X whichremains thus directly available for a further clathration step.

2. A process following claim 1 wherein X is selected from the groupconsisting oif Alpha-phenylethylamine Alpha-phenylpropylamineAlpha-phenylbutylamine Alpha-phenylamylamine Alpha-phenylisoamylamineAlpha-phenylhexylamine Alpha-phenylisohexylamineAlpha-phenylheptylamin'e Alpha- (m-tolyl) ethylamine Alpha- (p-tolylethylamine Alpha- (p-ethylphenyl) ethylamine Alpha- (p-tolyl) butylamineAlpha- (p tolyl) heptylamine Alphap-fluorophenyl) ethylamine Alpha-(o-chl orophenyl) ethyl amine Alpha- (m-chlorophenyl) ethylamine Alpha-(p-chlorophenyl) ethylamine Alpham-bromophenyl) ethyl amine Alpha-(p-bromophenyl ethylamine Alpha- (p-iodophenyl ethylamine Alpha-(p-chlorophenyl) propylamine Alpham-bromophenyl propylamine Alpha-(p-bromophenyl propylamine Alpha- (p-bromophenyl butylamine Alpha-(p-chlorophenyl) amylamine Alphap-bromophenyl amylamine Alpha-(p-fluorophenyl) isoamylamine Alphap-chlorophenyl) isoamylarnine Alpha-(p-bromophenyl isoamylamine Alpha- (p-chlorophenyl) hexylamineAlphap-bromophenyl hexylamine Alpha- (m-bromophenyl heptylamineAlphap-bromophenyl heptylamine Alph a (p-methoxyphenyl ethylamine Alpha-(p-butoxyphenyl) ethylamine Alpham-nitrophenyi )ethylamine Alph a-3,4-dime-thylphenyl) ethylamine Alph a- 3 ,4-dimethylphenyl)bu1tylamineAlpha-( 3 ,4-dimethylphenyl) heptylamine Alpha- 3 ,5 -dimethylphenyl)ethylamine Alpha- 3 ,4,5-trirnethylphenyl ethylamine Alpha-( 3 ,4,S-triethylphenyl ethylamine 30 Alpha-(3,4,5-trimethylphenyl)propylamineAlpha- 3 ,4-dichloropl1enyl ethylamine Alpha- 3 ,4-dibromophenyl)ethylamine Alpha- 3,4-dichlorophenyl) bu-tylamine Alpha- 3,4-dichlorophenyl) heptylamine 3. A process of resolving a mixture oforganic compounds, said mixture including an aromatic compound selectedfrom the group consisting of benzene, mono-, diand trialkylbenzeneswherein each alkyl radical has no more than 3 carbon atoms, ringsubstituted monohaloderivatives of benzene and of monoalkylbenzenies,dihalobenzenes, styrene, cyclohexyltoluenes, tetraline, naphthalene, andmonoand d-ialkylnaphthalenes wherein each alkyl radical has no more than3 carbon atoms, by clathration of said aromatic compound with a Wernercomplex Ni(CNS) X wherein X is a primary arylalkylamine of generalformula:

wherein R is a primary alkyl radical of l to 6 carbon atoms and R is anaroma-tic radical selected from the group consisting of phenyl, mono-,di-, and rtrialkylsubstituted phenyl radicals wherein substitutionoccurs at any of the 3, 4 and 5 positions of said phenyl radical, saidalkyl substituents having each less than 3 carbon atoms, phenyl radicalssubstituted by a polar radical selected from the group consisting ofhalogen, nitro, alkoxy containing 1 to 5 carbon atoms andN,N-dialkylamino wherein the alkyl portions contain 1 to 2 carbon atoms,and 3,4 dihalophenyl radicals, said resolution comprising reacting theWerner complex Ni(CNS) X with 2 moles of the amine X in the presence ofthe mixture to be resolved thereby forming a clathrate of the Wernercomplex Ni(CNS) X with said aromatic compound, recovering by heating theselectively absorbed aromatic compound with simultaneous dissociation ofthe complex Ni( CNS) X into the corresponding complex Ni (CNS X and 2free moles of the amine X, said 2 moles accompanying the liberatedaromatic compound, and recovering said amine from said aromaticcompound, this recovered amine and the complex Ni(CNS)- X obtained bythe hereabove dissociation being thus available for a furtherolathration step.

4. A process following claim 3 wherein X is selected from the groupconsisting of:

Alpha-phenylethyl amine Alpha-phenylpropylamine Alpha-phenylbutylamineAlpha-phenylamylamine Alpha-phenylisoamylamine Alpha-phenylhexylamineAlpha-phenylisohexylamine Alpha-phenylheptylamine Alpham-ltolyl)ethylamine Alpha- (p-tolyl) ethylamine Alphap-ethylphenyl) ethylamineAlpha- (p-tolyl) butylamine Alphap-tolyl) heptyl amine Alpha-(p-fiuorophenyl) ethylamine Alpha- ('o-chlorophenyl ethyl amine Alpha-(m-chlorophenyl) ethylamine Alphap-chloropltenyl) ethylamine Alpha-(m-bromophenyl) ethylamine Alpha- (p-bromophenyl) ethylamine A'lpha-(p-iodophenyl) ethyl amine Alpha- (p-chlorophenyl propyl amine Alpha-(m-bromophenyl )propylamine Alpha- (p-bromophenyl propylarnine Alpha-(p-bromophenyl) butylamine Alpha- (p-chlorophenyl) amylamine 31 7 Alpha-(p-b romophenyl) amylamine Alpha-(p-fluorophenyl)is0amy1amine A1pha-(p-chlorophenyl )isoamylamine Alpha- (p-bromophenyl )iso amylamine Alpha-(p-chlorophenyl) hexylami ne Alpha- (p-bromophenyl hexylamine' Alpha-(m-bromophcnyl heptylamine Alphap-bromophenyl hepmylamine Alpha-(p-methoxyphenyl)ethylamine Alpha- (p-butoxyphenyl ethylamine Alpha-(m-n=itrophenyl) ethyl amine Alpha 3 ,4-dimethylpheny1 ethylamine Alpha-3 ,4-dimethy1phenyl butylamine Alpha- 3 ,4-dimethylpheny1 heptylamineAlpha- 3 ,5 -dimethy1phenyl) ethylamfine Alpha-( 3 ,4, 5 -trimethy1pheny1) ethylamine Alpha-( 3 ,4,5-1triethy1phe11yl )ethylamineA-lpha- 3 ,4, 5-t1'imkethylphenyl) propylamine 7 32 1 Alpha-3,4-dich1oroplmenyl) ethylamine Alph a- 3,4-dibrom0pheny1) ethyl amineAlpha- 3 ,4-dichlorophenyl butylamine Alpha- 3 ,4-dichlorophenylheptylamine References Cited by the Examiner UNITED STATES PATENTS2,769,851 11/56 Schaefier 260 "674 2,798,891 7/57 'Schaeffer ;126O-4393/58 56116161161: 1 260-674 OTHER. REFERENCES TOBIAS E.- LEVOW, PrimaryExaminer.

1. A PROCESS OF RESOLVING A MIXTURE OF ORGANIC COMPOUNDS, SAID MIXTUREINCLUDING AN AROMATIC COMPOUND SELECTED FROM THE GROUP CONSISTING OFBENZENE, MONO-, DI- AND TRIALKYBENZENES WHEREIN EACH ALKYL RADICAL HASNO MORE THAN THREE CARBON ATOMS, RING SUBSTITUTED MONOHALODERIVATIVES OFBENZENE AND OF MONOALKYLBENZENES, DIHALOBENZENES, STYRENE,CYCLOHEXYLTOLUENES, TETRALINE,